The finding needs confirmation, the researchers stress in the Archives of Neurology. They studied data from about 3,300 elderly people in Cache County, Utah.
Participants were screened for Alzheimer's disease, with 104 new cases noted in a three-year period. People taking drugs for high blood pressure -- especially certain diuretics -- were less likely to have developed Alzheimer's, the study shows.
The researchers included Ara Khachaturian, PhD, of Khachaturian and Associates in Potomac, Md.
About the Study
Instead, Khachaturian's team did an observational study. They noted participants' drugs and new cases of Alzheimer's.
Participants were at least 65 years old at the study's start. A check of their medication bottles showed that about 45% were taking drugs to treat high blood pressure.
"By far the greatest effect was seen with potassium-sparing diuretics, which were associated with more than a 70% reduction in risk of Alzheimer's disease," the researchers write.
Diuretics, sometimes called "water pills," work in the kidneys and flush excess water and sodium from the body.
Potassium-sparing diuretics avoid flushing out potassium, a mineral that may lower the odds of developing Alzheimer's, write Khachaturian and colleagues.
Nearly half of participants who took potassium-sparing diuretics also took another blood pressure drug. Their data show that potassium-sparing diuretics were still linked to a lower risk of Alzheimer's disease.
The researchers also took other factors into account, including participants' age, sex, blood pressure, education, and conditions that might make Alzheimer's more likely. The results held.
Past studies on the topic have had mixed results, so it's too soon to be sure of the findings, Khachaturian's team notes.